That could be you. He's using the good 'ol "boost right before the blue shell hits you" trick, which has been available in a number of previous Mario Karts. You only have a few moments to pull the maneuver off, so the timing is tricky, but it's definitely worth learning how to do if you want to stay in first place.

Here's a tutorial by AbdallahSmash026 on how to avoid the blue shell with the mushroom—but it's not the only item you can use to do it. You can also use a super horn, which is a new thing unique to Mario Kart 8. And unlike the mushroom, you're actually likely to get the super horn while you're in first place.

Mastering this technique means you'll be able to have lots of slo-mo badass moments like the ones in this video by Rodriguezjr: